JP2008533212A - Coated fine particles, method for producing the same, and conductive fine particles - Google Patents

Abstract

Provided are coated fine particles that are flexible and excellent in elasticity, and have good adhesion to a metal, a method for producing the same, and conductive fine particles using the coated fine particles as core fine particles.
A coated fine particle having a polymer coating layer formed by ring-opening and / or polycondensation reaction on the surface of a core fine particle made of an organic material or an organic-inorganic composite material, and a method for producing the coated fine particle A method for producing coated fine particles, wherein the polymer coating layer is formed by ring-opening and / or polycondensation reaction in the presence of a surfactant in an aqueous medium in which the core particles are dispersed.
[Selection] Figure 4

Description

  The present invention relates to coated fine particles having good adhesion to a metal, a method for producing the same, and conductive fine particles using the coated fine particles.

  Polymers include spacers for cell gaps (or panel gaps) such as display displays such as liquid crystal display devices and touch panels, conductive gap members such as conductive adhesives and anisotropic conductive adhesives for mounting microelements, etc. Particles are widely used. In these applications, it is required that the particle shape is substantially uniform, flexible and excellent in elasticity, and from such a viewpoint, as a material of polymer particles, an organic material, an organic component and an inorganic component are used. Organic-inorganic composite materials using a combination of these are used.

  For example, Patent Document 1 discloses organic resin fine particles made of an amino resin (for example, urea resin, melamine resin, guanamine-based resin). Since these amino resin fine particles have a large number of functional groups on the surface of the fine particles, and have good adhesion to metal and easy formation of a metal coating layer, they are widely used as base particles for conductive fine particles. Yes.

On the other hand, Patent Document 2 discloses organic-inorganic composite fine particles including an organic polymer skeleton and a polysiloxane skeleton. According to this technique, it is described that fine particles having desired characteristics can be obtained by controlling the type and amount of the fine particle constituent material.
Japanese Examined Patent Publication No. 7-17723 JP 2003-183337 A JP 2001-126532 A

  However, since the amino resin fine particles have a dense cross-linked structure, the particles are too hard to be compressed and deformed. For example, even when used as conductive fine particles between electrodes, the contact area with the electrode surface cannot be expanded, and the contact resistance It was difficult to reduce. In addition, if the amount of compressive deformation is increased in order to increase the contact area, the particles are destroyed when the strain of the particles becomes large, so that there is a problem that connection reliability is inferior. On the other hand, although the organic-inorganic composite fine particles have flexibility, they are inferior in adhesion to the metal compared to the amino resin fine particles, so that the metal coating layer applied on the surface of the organic-inorganic composite fine particles can follow the deformation of the fine particles. There was a problem of peeling off. In Patent Document 3, a technique for improving plating adhesion to silicone fine particles has been proposed in order to solve such a problem. However, problems such as melting and aggregation of the silicone resin in the etching process performed prior to the plating process have not been completely solved, and there is room for further improvement.

  The present invention has been made in view of the above circumstances, and its object is to provide coated fine particles that are flexible and excellent in elasticity and also have good adhesion to metal, a method for producing the same, and the coated fine particles as core fine particles. It is to provide conductive fine particles.

  The coated fine particles of the present invention capable of solving the above-mentioned problems are those having a polymer coating layer formed by ring-opening and / or polycondensation reaction on the surface of core fine particles made of an organic material or an organic-inorganic composite material. It has a gist.

  The present inventors proceeded with studies to obtain fine particles having excellent flexibility and elasticity, and good adhesion to metal, ensuring the above characteristics with different materials, and integrating these, the above problems With the idea that they could be satisfied, trial and error were repeated. Of course, the above characteristics cannot be fully expressed by simply integrating the materials, and the point of the present invention is that the fineness and elasticity of the fine particles are the core fine particles that constitute the central part of the particles, Adhesiveness is ensured by the polymer coating layer covering the core fine particles, and the polymer coating layer is formed on the surface of the core fine particles by ring-opening and / or polycondensation reaction. That is, since a uniform polymer coating layer is present on the surface of the core fine particles, the coated fine particles have excellent flexibility and elasticity as well as excellent adhesion to metal.

  The method for producing coated fine particles of the present invention is a method for producing coated fine particles having a polymer coating layer on the surface of core fine particles made of an organic material or an organic-inorganic composite material, and is an aqueous system in which the core particles are dispersed The gist of the invention is that the polymer coating layer is formed by ring-opening and / or polycondensation reaction in the presence of a surfactant in a medium.

  According to the present invention, coated fine particles can be obtained which can control fine particle properties such as flexibility and elasticity and have good adhesion to a metal. In addition, since the conductive fine particles according to the present invention are based on the coated fine particles, they have good adhesion to metals, and are used as conductive fine particles used for, for example, anisotropic conductive materials. Even in this case, the conductor layer hardly peels off.

  The coated fine particles of the present invention are characterized by having a polymer coating layer formed by ring-opening and / or polycondensation reaction on the surface of core fine particles made of an organic material or an organic-inorganic composite material.

  As described above, the point of the present invention is that a polymer coating layer having excellent physical properties (for example, flexibility and elasticity) required for the core fine particles and excellent adhesion to the metal is uniformly formed on the surface of the core fine particles. It is in the point. Therefore, first, the polymer coating layer will be described.

  The polymer coating layer according to the present invention is to impart good adhesion to the metal to the coated fine particles of the present invention. In the aqueous medium in which the core particles are dispersed, a surfactant (general formula described later) is used. In the presence of (compound represented by (1)), the compound serving as a raw material for the polymer coating layer is subjected to ring-opening and / or polycondensation reaction to form on the surface of the core fine particles.

  Examples of the raw material for the polymer coating layer include a compound (A) and a compound (B) (described later). The compound (A) is a mixture of at least one selected from the group consisting of urea, thiourea, melamine, benzoguanamine, acetoguanamine and cyclohexylguanamine (hereinafter referred to as amino compound) and formaldehyde, or from these amino compounds It is preferable to include an initial condensation compound obtained by reacting at least one selected with formaldehyde. In addition, it is preferable to use an initial condensation compound as a compound (A) from the point that affinity with water is high and formation of a polymer coating layer is quick.

  Here, the compound obtained by the reaction of the amino compound and formaldehyde is a so-called amino resin (urea resin, melamine resin, guanamine resin), and the initial condensation compound is a compound that is a precursor of the amino resin. It is. That is, by using the compound (A), a polymer coating layer that essentially includes an amino resin structure is formed.

  In addition, the said initial condensation compound can become a structural component of urea resin, when (i) at least 1 sort (s) of urea and thiourea (henceforth a urea type compound) and formaldehyde are used as a compound (A). It becomes an initial condensation compound, and when (ii) melamine and formaldehyde are used, at least one selected from the group consisting of melamine resin, (iii) benzoguanamine, acetoguanamine and cyclohexylguanamine (hereinafter referred to as guanamine-based compound) and formaldehyde When is used, it becomes an initial condensation compound that can be a constituent component of the guanamine-based resin. In the case of (iv) one obtained by reacting two or more of urea compounds, melamines and guanamine compounds with formaldehyde, 2 of urea resins, melamine resins and guanamine resins. It becomes an initial condensation compound that can be a constituent component of a resin in which species or more are mixed. As said initial condensation compound, any 1 type of these initial condensation compounds may be used, and 2 or more types may be used together.

  Preferred amino compounds for the synthesis of the initial condensation compound are preferably urea compounds, melamine, co-condensates of urea compounds and melamine, and co-condensates of melamine and guanamine compounds, more preferably Is a urea-based compound, a melamine, and a co-condensate of urea-based compound and melamine compound, more preferably a melamine and a co-condensate of urea-based compound and melamine.

  In addition, other amino compounds other than those described above may be used in combination, and examples of such other amino compounds include capryguanamine, amelin, amelide, ethylene urea, propylene urea, and acetylene urea. When another amino compound is used, the above amino compound and the other amino compound are combined and handled as an amino compound serving as a raw material for the initial condensation compound (or included in the polymer composite layer).

  The formaldehyde to be reacted with the amino compound is not particularly limited as long as it forms formaldehyde in the reaction system. In the reaction for obtaining the initial condensation compound, since water is generally used as a solvent, in addition to an aqueous formaldehyde solution (formalin), trioxane or paraformaldehyde may be added to water so that formaldehyde can be generated in water. .

  Specific reaction forms for obtaining the above initial condensation compound include a method of reacting an amino compound with an aqueous formaldehyde solution (formalin) or an aqueous solution in which trioxane or paraformaldehyde is added to water. The method of making it react is mentioned preferably. Among these, the former method is preferable because it does not require a preparation tank for an aqueous formaldehyde solution and formalin is easily available. The above reaction may be in a form in which an amino compound and formaldehyde react in a mixed state. For example, in addition to a form in which an amino compound is added to an aqueous formaldehyde solution, an aqueous formaldehyde solution is added to the amino compound. Also good. The above reaction is preferably carried out with stirring by a known stirring device or the like.

  In the reaction for obtaining the initial condensation compound, the molar ratio “amino compound (mol) / formaldehyde (mol)” between the amino compound and formaldehyde is preferably 1 / 0.5 to 1/10, more preferably 1 / 1 to 1/8 or less, more preferably 1/1 to 1/6 or less. When the compounding ratio (molar ratio) of the amino compound and formaldehyde is out of the above range, either compound remains in the reaction system in a large amount without being reacted.

  When water is used as the solvent, the addition amount of the amino compound and formaldehyde with respect to water, that is, the concentration of the amino compound and formaldehyde at the time of charging is preferably higher as long as the reaction is not hindered.

The initial condensation compound preferably has a water miscibility (an index of the degree of polycondensation rate) of 100% or more, more preferably 200% or more, and preferably 5000% or less, more preferably 3000. % Or less. If the water miscibility exceeds the above range, it means that the hydrophilicity of the initial condensation compound is high. In such a case, it tends to take a long time to form the polymer coating layer. On the other hand, when the water miscibility is less than the above range, it is difficult to control the reaction when forming the polymer composite layer, and it is difficult to obtain the characteristics (flexibility, mechanical strength, plating property, etc.) of the polymer coating layer. May be. The water miscibility is an index of the degree of polymerization of the initial condensation compound obtained by the reaction between the amino compound and formaldehyde. When water is added dropwise to the initial condensation compound (5 g, 15 ° C.). This is a value obtained by multiplying the mass ratio “water (g) / initial condensation compound (g)” of the mass of water required for producing white turbidity to the initial condensation compound by 100.
Water miscibility = [water (g) / initial condensation compound (g)] × 100

  The degree of polycondensation rate of the initial condensation compound can be controlled by methods other than water miscibility, such as GPC (gel permeation chromatography) and LC (liquid chromatography), but can be easily implemented and reproduced. It is preferable to employ water miscibility from the viewpoint of good properties.

  The reaction of the initial condensation compound is preferably performed within a range of 65 to 75 ° C. Within such a temperature range, the progress of the reaction can be grasped over time and immediately based on the water miscibility described above, and the desired reaction end point (target point) can be accurately determined. This is because the reaction can be easily terminated by cooling the solution. The reaction time is not particularly limited, and may be appropriately determined while confirming the progress of the reaction.

  Moreover, as a raw material of the polymer coating layer, an epoxy compound (compound having an epoxy group) may be used as the compound (B) instead of the compound (A) or in addition to the compound (A). it can. Therefore, a polymer coating layer containing an epoxy resin formed by ring-opening / polycondensation of an epoxy compound is also included in the present invention. By including an epoxy resin, it is possible to obtain coated fine particles with higher flexibility and higher mechanical strength as well as adhesion to metal.

  The epoxy compound used as the raw material for the epoxy resin is preferably an epoxy compound having two or more epoxy groups in one molecule and exhibiting water solubility. For example, sorbitol polyglycidyl ester, (poly) glycerol polyglycidyl ester , Pentaerythritol polyglycidyl ester, glycidyl tris (2-hydroxyethyl) isocyanurate, trimethylolpropane polyglycidyl ester, neopentyl glycol diglycidyl ester, ethylene glycol diglycidyl ester, polyethylene glycol diglycidyl ester, propylene glycol diglycidyl ester, Examples thereof include polypropylene glycol diglycidyl ester and adipic acid diglycidyl ester. These may be used alone or in combination of two or more.

The epoxy compound preferably has a solubility in water of 50% by mass or more, more preferably 60% by mass or more, still more preferably 70% by mass or more, and particularly preferably 100% by mass. When the dissolution rate is within the above range, the formation of the epoxy resin layer (polymer coating layer) proceeds uniformly and quickly, and the excellent effects such as easy control of the thickness of the epoxy resin layer Is obtained. In addition, the solubility with respect to the water of the epoxy compound prescribed | regulated by this invention means the value calculated | required with the following measuring methods. In a 300 mL beaker, 25.0 g of a sample compound (epoxy compound) is precisely weighed, 225 g of water is added thereto, and the sample compound is dissolved by vigorous stirring for 1 hour with a magnetic stirrer, and then allowed to stand for 1 hour. Next, the undissolved sample compound (oil) precipitated at the bottom of the beaker is extracted, placed in a 10 mL (or 5 mL) graduated cylinder, and further placed for 30 minutes. ) To the first decimal place. The obtained value is substituted into the following formula to calculate the dissolution rate (%) of the sample compound (epoxy compound) in water.
Dissolution rate in water (%) = 100− (A / 21) × 100
(However, A in the above formula represents the liquid volume (mL) of the read sample compound.)

  The epoxy compound preferably has a weight average molecular weight of 300 or more and 10,000 or less, more preferably 300 or more and 5,000 or less. When the weight average molecular weight is within the above range, excellent effects such as easy control of the thickness of the epoxy resin layer (polymer coating layer) can be obtained. On the other hand, if the weight average molecular weight is less than the above range, it is difficult to obtain the effect of improving the flexibility by forming the epoxy resin layer, and it may be difficult to form a uniform epoxy resin layer. If the amount exceeds the above range, the viscosity of the reaction solution at the time of forming the polymer coating layer may rapidly increase, which may make stirring difficult. If forced stirring is performed at this time, the coated fine particles may be damaged or destroyed. There is a risk.

  When forming the said epoxy resin layer, you may add a crosslinking agent other than an epoxy compound. By using a crosslinking agent, the strength of the epoxy resin layer to be formed, and thus the strength of the coated fine particles can be further increased, and damage and destruction in the isolation and cleaning process of the coated fine particles can be effectively suppressed. The timing of addition of the crosslinking agent is not particularly limited, and may be added together with the epoxy compound or may be added before or after the addition of the epoxy compound, but preferably after the addition of the epoxy compound. .

  The crosslinking agent is not particularly limited, and examples thereof include sodium diethyldithiocarbamate (including hydrate), diethylammonium diethyldithiocarbamate (including hydrate), dithiosuccinic acid and dithiocarbonate. These may be used alone or in combination of two or more. Moreover, although the usage-amount of the said crosslinking agent is not limited, For example, it is preferable to set it as 1-100 mass parts with respect to 100 mass parts of epoxy compounds, More preferably, it is 5-80 mass parts. If the amount of the crosslinking agent used is less than the above range, it may be difficult to control the thickness of the epoxy resin layer, and if it exceeds the above range, the reaction with the epoxy group in the epoxy compound becomes excessive, There is a possibility that an epoxy resin layer rich in flexibility and adhesion to metal cannot be formed.

As the surfactant that coexists in the reaction system when the polymer coating layer is formed, the compound represented by the following formula (1) or an emulsifier exemplified in the description of the core fine particles described later, for example, anionic Surfactants, cationic surfactants, nonionic surfactants, amphoteric surfactants, and polymeric surfactants can be mentioned.
R ¹ — (CH ₂ —CH ₂ —O—) _n —X _m —R ² (1)

  The surfactant is used to maintain the dispersed state of the core fine particles in the reaction system (dispersant) and to uniformly form the polymer coating layer on the surface of the core fine particles. The surfactant represented by 1) also becomes a constituent component of the polymer coating layer. That is, the polymer coating layer according to the present invention includes intermolecular molecules such as a core particle and a surfactant, and a hydrophobic interaction acting between the surfactant and the compound (A) and / or the compound (B). It is formed using power. When the polymer coating layer is formed in the absence of the surfactant as described above, the ring-opening reaction of the compound (A) and / or the compound (B) is performed not only on the surface of the core fine particles. The polycondensation reaction proceeds, and in addition to the coated fine particles according to the present invention, a polymer component derived from the compound (A) and the compound (B) not containing the core fine particles is generated. In order to prevent such problems, it is preferable to use a surfactant. From the viewpoint of forming a uniform polymer coating layer on the surface of the core fine particles, it is preferable to use the surfactant represented by the above formula (1) among the surfactants exemplified above.

In the above formula (1), R ¹ represents a hydrophobic group containing an aliphatic group or an aromatic group. For example, pentyl group, hexyl group, heptyl group, octyl group, decyl group, octadecyl group, stearyl group, Examples thereof include aliphatic hydrocarbon groups such as behenyl groups, and aromatic hydrocarbon groups such as phenyl groups, benzyl groups, tolyl groups, xylyl groups, biphenyl groups, and naphthyl groups. The number of carbon atoms of the hydrophobic group is preferably 5 or more and 25 or less (more preferably 18 or less). When the number of carbon atoms is too small, the dispersion of the core fine particles tends to be insufficient due to the hydrophilicity derived from the ethylene oxide chain. On the other hand, when the number of carbon atoms is too large, the hydrophobicity becomes too high. This is because the surfactant is difficult to dissolve in water (reaction solvent).

In the above formula (1), [— (CH ₂ —CH ₂ —O—) _n ] is a polymer chain having a polyether structure (polyethylene oxide structure), and the number n of the polyether structures is 3 or more. More preferably, it is 5 or more, It is preferable that it is 85 or less, More preferably, it is 60 or less, More preferably, it is 50 or less. If the polyether structure is too small (depending on the balance with the hydrophobic group R ¹ described above), the compound may be difficult to dissolve in the aqueous medium. It tends to be too difficult to be incorporated into the polymer coating layer. If n is within the above range, a part of the surfactant reacts with the compound (A) and the compound (B) and is taken into the polymer coating layer when the polymer coating layer is formed. Thus, it is possible to impart appropriate flexibility to the coated fine particles, which in turn contributes to an improvement in the mechanical strength of the coated fine particles.

In the general formula (1), X is derived from a group capable of reacting (binding reaction) with at least one group selected from the group consisting of an amino group, an imino group, and a carboxyl group, and this reaction (binding reaction). The group formed later is represented. In the formula (1), m represents 1 or 0. Here, the amino group, imino group and carboxyl group can be present in a polymer having an R ² polyamine structure, which will be described later, or in a polymer having a polycarboxylic acid structure. It means a carboxyl group.

The group represented by X is, for example, a group formed by a reaction between a functional group derived from R ² and a group represented by X ² in the following general formula (3). Specifically, “—CH ₂ —CH ₂ —S—” derived from the group represented by the structural formula (b), “—CO—” derived from the isocyanate group, “—CO—NH—CH ₂ — derived from the oxazoline group. “CH ₂ —”, “—CH (OH) —” derived from an aldehyde group, “—CO—” derived from a carboxyl group, “—NH—” derived from an amino group, or “= derived from an imino group” N- "can be exemplified.

In the formula (1), R ² represents a polymer group having a polyamine structure or a polycarboxylic acid structure having a weight average molecular weight of 300 to 100,000 (more preferably 300 to 50,000). If the weight average molecular weight is too small, it is difficult to precipitate as an insoluble matter, and it may take a long time to form the polymer coating layer, and the strength of the polymer coating layer may be insufficient. If it is too large, the viscosity of the entire reaction system will rise rapidly, and stirring may become difficult.

  The polymer group having a polyamine structure is not limited, but a polymer group having a polyamine structure containing a primary amino group and / or a secondary amino group, such as polyethyleneimine, polyamine, polyetheramine, polyvinyl At least selected from the group consisting of amine, modified polyvinylamine, polyalkylamine, polyamide, polyamine epichlorohydrin, polydialkylaminoalkyl vinyl ether, polydialkylaminoalkyl (meth) acrylate, polyallylamine, polyethyleneimine grafted polyamidoamine and protonated polyamidoamine Examples thereof include a polymer group having one type of structure.

  The polymer group having the polycarboxylic acid structure is not limited, but acrylic acid, methacrylic acid, α-hydroxyacrylic acid, crotonic acid, phthalic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, aconitic acid, And a polymer group having a structure of a water-soluble polycarboxylic acid obtained by polymerization of a monomer component containing 30 mol% or more of an unsaturated carboxylic acid such as vinyl acetate.

The method for preparing the surfactant represented by the general formula (1) is not particularly limited. For example, the following general formula (2) or the following general formula (3) is added to an aqueous solution of polyamine or polycarboxylic acid with stirring. It is preferable to employ a method of dropping a compound represented by
^{_{R 1 - (CH 2 -CH 2}} -O-) n-1 -X 1 (2)
X ¹ represents a group represented by the following structural formula (a):

R ¹ — (CH ₂ —CH ₂ —O—) _n —X ² (3)
X ² is a group represented by the following structural formula (b):

It represents any one selected from the group consisting of an isocyanate group, an oxazoline group, an aldehyde group, a carboxyl group, an amino group and an imino group. That is, X ² represents a group capable of reacting (binding reaction) with at least one group selected from the group consisting of an amino group, an imino group, and a carboxyl group. )

  When the compound represented by the general formula (2) is used for the preparation of the surfactant represented by the formula (1), the group represented by X in the general formula (1) does not exist. (Ie, m = 0). On the other hand, when the compound represented by the general formula (3) is used for the preparation of the surfactant represented by the above formula (1), the group represented by X in the above general formula (1) exists. (Ie, m = 1).

  The reaction temperature at the time of preparing the above-mentioned surfactant is not particularly limited. However, when polyamine is used, it is preferably 10 to 90 ° C, more preferably 15 to 80 ° C, and polycarboxylic acid is used. It is preferable to set it as 20-100 degreeC, More preferably, it is 20-90 degreeC. Although reaction time is not limited, It is preferable to set it as 0.5 to 5 hours, More preferably, it is 1 to 5 hours.

  In the present invention, other compounds may be used together with the surfactant represented by the above formula (1) as long as the effects of the present invention are not hindered. For the convenience of carrying out the reaction for forming the polymer coating layer in an aqueous medium, it is desirable that the other compounds are also water-soluble. Examples of other compounds that can be used in the present invention include polyvinyl pyrrolidone, polyvinyl alcohols, various surfactants other than the above formula (1), natural polymer dispersants such as gelatin and gum arabic, styrene / maleic acid, and the like. Examples thereof include synthetic polymer dispersants such as copolymers and salts thereof.

  Next, the core fine particles according to the present invention will be described. The core fine particles serving as the base material for the coated fine particles according to the present invention greatly affect the flexibility, elasticity and mechanical properties of the coated fine particles. The material of the core fine particles is not particularly limited, and any of organic materials, organic-inorganic composite materials, and inorganic materials can be employed. Examples of organic materials include linear polymers such as polystyrene, polymethyl methacrylate, polyethylene, polypropylene, polyethylene terephthalate, polybutylene terephthalate, polysulfone, polycarbonate, and polyamide; divinylbenzene, hexatriene, divinyl ether, divinylsulfone, diallylcarbinol, Alkylene diacrylate, oligo or polyalkylene glycol diacrylate, oligo or polyalkylene glycol dimethacrylate, alkylene triacrylate, alkylene tetraacrylate, alkylene trimethacrylate, alkylene tetramethacrylate, alkylene bisacrylamide, alkylene bismethacrylamide, both end acrylic modified polybutadiene Oligomer alone or other polymerization A network polymer obtained by polymerization with a monomer; an amino resin (for example, benzoguanamine, melamine or urea) and an amino resin obtained by polycondensation reaction with formaldehyde, divinylbenzene is polymerized alone or in combination with other vinyl monomers. Examples thereof include divinylbenzene crosslinked resin particles obtained by polymerization. As an organic-inorganic composite material, it is reacted with a polysiloxane using a silicon compound having a hydrolyzable silyl group as a raw material and a polymerizable monomer having a polymerizable group (eg, vinyl group, (meth) acryloyl group). Examples thereof include organic-inorganic composite particles obtained. Examples of the inorganic material include glass, silica, and alumina. In addition, the thing which consists of an organic material or an organic inorganic composite material from the point that the design of the characteristic of a core fine particle can be performed comparatively freely is preferable.

  As the organic / inorganic composite fine particles, polymer fine particles in which a polysiloxane skeleton and an organic polymer skeleton form a three-dimensional network structure are particularly preferable. An example of a method for producing such polymer fine particles is shown below.

  The organic-inorganic composite fine particle is a polymer fine particle comprising a polysiloxane skeleton as an inorganic part and an organic polymer skeleton as an organic part, and at least one carbon atom in the organic polymer skeleton is a polysiloxane. It has an organic silicon atom in the molecule that is directly chemically bonded to the silicon atom in the skeleton (chemical bond type).

  The polysiloxane preferably has an unsaturated group that can bond to the organic polymer skeleton, and preferably has a vinyl group, for example. The polysiloxane having a vinyl group has a polysiloxane skeleton structure obtained by hydrolyzing and condensing a compound raw material containing a silicon compound having a vinyl group. For example, a hydrolyzable silicon compound is converted into water. It is obtained by hydrolysis and condensation in a solvent containing The timing of introduction of the vinyl group is not particularly limited. For example, a mode in which a hydrolyzable silicon compound has a vinyl group, a hydrolyzable silicon compound having no vinyl group is hydrolyzed / condensed and used as a seed. After producing particles (polysiloxane having no vinyl group), the seed particles (polysiloxane having no vinyl group) and a hydrolyzable silicon compound having a vinyl group are hydrolyzed / condensed. Any embodiment in which a vinyl group is introduced into siloxane can be employed. In the latter case, a radical polymerization reaction with the polymerizable component may be performed simultaneously with the hydrolysis and condensation of the seed particles and the hydrolyzable silicon compound having a vinyl group.

Although the said hydrolysable silicon compound is not specifically limited, For example, the silane compound represented by following General formula (4) and its derivative (s) can be used.
^{_{R 3 l SiX 4-l (}} 4)
(Here, R ³ may have a substituent, and represents at least one group selected from the group consisting of an alkyl group, an aryl group, an aralkyl group and an unsaturated aliphatic group, and X represents a hydroxyl group, an alkoxy group. And at least one group selected from the group consisting of a group and an acyloxy group, and l represents an integer from 0 to 3.)

  Examples of the silane compound represented by the general formula (4) include the following. For l = 0, tetrafunctional silanes such as tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, tetrabutoxysilane; and for l = 1, methyltrimethoxysilane, methyltriethoxysilane, ethyl Trimethoxysilane, ethyltriethoxysilane, hexyltriethoxysilane, decyltrimethoxysilane, phenyltrimethoxysilane, benzyltrimethoxysilane, naphthyltrimethoxysilane, methyltriacetoxysilane, β- (3,4-epoxycyclohexyl) ethyl Trimethoxysilane, 3-glycidoxypropyltrimethoxysilane, vinyltrimethoxysilane, 3- (meth) acryloxypropyltrimethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane Trifunctional silanes of 1; bifunctional silanes such as dimethylsilane, dimethyldiethoxysilane, diacetoxydimethylsilane, dimethoxydiphenylsilanediol, and the like for l = 2; trimethyl, trimethylethoxy for l = 3 And monofunctional silanes such as silane and trimethylsilanol.

  The silane compound may be used alone or in combination of two or more. In addition, in the said General formula (4), when only the silane compound and its derivative which are 1 = 3 are used as a raw material, composite particle | grains are not obtained.

Examples of the hydrolyzable silicon compound having a vinyl group include those having a polymerizable reactive group represented by the following general formulas (5), (6) and (7).
^{_{CH 2 = C (-R 4)}} -COOR 5 - (5)
(Here, R ⁴ represents a hydrogen atom or a methyl group, and R ⁵ represents an optionally substituted divalent organic group having 1 to 20 carbon atoms.)
^{_{CH 2 = C (-R 6)}} - (6)
(Here, R ⁶ represents a hydrogen atom or a methyl group.)
^{_{CH 2 = C (-R 7)}} -R 8 - (7)
(Here, R ⁷ represents a hydrogen atom or a methyl group, and R ⁸ represents an optionally substituted divalent organic group having 1 to 20 carbon atoms.)

  Examples of the polymerizable reactive group represented by the general formula (5) include an acryloxy group and a methacryloxy group. Examples of the silicon compound of the general formula (4) having the organic group include γ- Methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-acryloxypropyltrimethoxysilane, γ-acryloxypropyltriethoxysilane, γ-methacryloxypropyltriacetoxysilane, γ-methacryloxyethoxypropyltri Methoxysilane (or γ-trimethoxysilylpropyl-β-methacryloxyethyl ether), 11-methacryloxyundecamethylenetrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyl Chill diethoxy silane, etc. γ- acryloxypropylmethyldimethoxysilane can be exemplified.

  Examples of the polymerizable reactive group represented by the general formula (6) include a vinyl group and an isopropenyl group. Examples of the silicon compound of the general formula (4) having the organic group include a vinyl trimethyl group. Methoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, 4-vinyltetramethylenetrimethoxysilane, 8-vinyloctamethylenetrimethoxysilane, 3-trimethoxysilylpropylvinylether, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane, Examples thereof include vinylmethyldiacetoxysilane. These may be used alone or in combination of two or more.

  Examples of the polymerizable reactive group represented by the general formula (7) include a 1-alkenyl group, a vinylphenyl group, an isoalkenyl group, and an isopropenylphenyl group, and the general formula having the organic group. Examples of the silicon compound (4) include 1-hexenyltrimethoxysilane, 1-hexenyltriethoxysilane, 1-octenyltrimethoxysilane, 1-decenyltrimethoxysilane, γ-trimethoxysilylpropyl vinyl ether, ω -Trimethoxysilylundecanoic acid vinyl ester, p-trimethoxysilylstyrene, p-triethoxysilylstyrene, p-trimethoxysilyl-α-methylstyrene, p-triethoxysilyl-α-methylstyrene, N-β- ( N-vinylbenzylaminoethyl-γ-aminopropi ) Trimethoxysilane hydrochloride, 1-hexenyl methyldimethoxysilane, and the like 1-hexenyl diethoxy silane. These may be used alone or in combination of two or more.

  The above polysiloxane is obtained by hydrolyzing and condensing the hydrolyzable silicon compound group in a solvent containing water. About hydrolysis and condensation, arbitrary methods, such as lump, a division | segmentation, and a continuation, can be taken. In addition, in the hydrolysis and condensation, a catalyst such as ammonia, urea, ethanolamine, tetramethylammonium hydroxide, alkali metal hydroxide, or alkaline earth metal hydroxide may be used. Further, in the solvent, an organic solvent may be present in addition to water and the catalyst.

  The organic solvent is not particularly limited. For example, methanol, ethanol, isopropanol, n-butanol, isobutanol, sec-butanol, t-butanol, pentanol, ethylene glycol, propylene glycol, 1,4-butanediol Alcohols such as acetone, ketones such as methyl ethyl ketone, esters such as ethyl acetate, (cyclo) paraffins such as isooctane and cyclohexane, ethers such as dioxane and diethyl ether, and aromatic hydrocarbons such as benzene and toluene Etc. are preferred. These may be used alone or in combination of two or more.

  The hydrolysis and condensation reaction is carried out by adding the above-mentioned silicon compound group and organic solvent to a solvent containing water and stirring in a temperature range of 0 to 100 ° C., preferably 0 to 70 ° C., for 30 minutes to 100 hours. Just do it. At this time, the water concentration with respect to the total amount of the reaction mixture is 10 to 99.99% by mass, the catalyst concentration is 0.01 to 10% by mass, the organic solvent concentration is 0 to 90% by mass, and the concentration of the silicon compound group is It is preferable to set it as 0.1-30 mass%. Further, the addition time of the silicon compound group is preferably 0.001 to 500 hours, and the reaction temperature is preferably 0 to 100 ° C. In addition, when using the particle | grains obtained by carrying out a hydrolysis / condensation reaction beforehand as a seed particle, it is preferable to set the density | concentration of a seed particle to 0.1-30 mass% with respect to the total amount of a reaction liquid mixture. .

  In addition, particles obtained by hydrolysis and condensation reaction are charged in advance into a synthesis system as seed particles, and the above-described silicon compound group is added thereto to grow the seed particles, thereby obtaining polysiloxane particles. You can also. In this manner, the silicon compound group is hydrolyzed and condensed under a suitable condition in a solvent containing water, whereby particles are precipitated and a slurry is generated. The precipitated particles are obtained by using the above-described silicon compound having a vinyl group as an essential component, and thus become polysiloxane particles having a vinyl group. Here, the appropriate conditions are not particularly limited. For example, the slurry containing seed particles (preferably having a concentration of 0.1 to 20% by mass) obtained in advance by hydrolysis and condensation reaction may be used for the above-mentioned hydrolysis. Conditions under which the concentration of the decomposable silicon compound is 20% by mass or less, the water concentration is 50% by mass or more, and the catalyst concentration is 10% by mass or less based on the total amount of the reaction mixture.

  The shape of the polysiloxane particles may be any particle shape such as a spherical shape, a needle shape, a plate shape, a scale shape, a pulverized shape, a bowl shape, an eyebrows shape, and a confetti shape, and is not particularly limited.

  The average particle size of the polysiloxane particles is not particularly limited, but is preferably 0.1 to 700 μm, more preferably 0.5 to 70 μm, and most preferably 1 to 50 μm. When the average particle diameter of the polysiloxane particles is within the above range, it is possible to exert an advantageous effect that absorption of a polymerizable component described later proceeds efficiently. On the other hand, if the average particle size of the polysiloxane particles is too small, the polymerization components described later may not be sufficiently absorbed. If it is too large, the mass of the particles will increase and the polymer in the reactor will become large. Precipitation of fine particles occurs and the particles tend to aggregate.

  The polysiloxane particles obtained as described above are particles that can easily absorb and retain a polymerizable component described later in the polysiloxane skeleton constituting the particles. This can be said to be because the polysiloxane particles have a degree of condensation suitable for absorbing a polymerizable component described later.

  Next, the polymerizable component to be polymerized with the polysiloxane particles will be described. The polymerizable component is not particularly limited, but considering compatibility with the polysiloxane particles, a radical polymerizable vinyl monomer or a bifunctional oligomer having two (meth) acryloyl groups in one molecule is used. It is preferable to do this.

  The radical polymerizable vinyl monomer is preferably a compound containing at least one ethylenically unsaturated group in the molecule, and may be appropriately selected so that the polymer fine particles can exhibit desired physical properties. Specifically, monomers having a hydroxyl group such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 2-hydroxybutyl (meth) acrylate; methoxypolyethylene glycol (meth) acrylate and the like Monomers having a polyethylene glycol component; butyl (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, isoamyl acrylate, lauryl (meth) acrylate, benzyl methacrylate, tetrahydrofluorate methacrylate Alkyl (meth) acrylates such as furyl; fluorine atoms including trifluoroethyl (meth) acrylate, tetrafluoropropyl (meth) acrylate, pentanefluoropropyl (meth) acrylate, octafluoroamyl (meth) acrylate, etc. (Meth) acrylates; aromatic vinyl compounds such as styrene, α-methylstyrene, vinyltoluene, α-chlorostyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, p-ethylstyrene; glycidyl (meta ) Acrylate, (meth) acrylic acid, (meth) acrylamide, (meth) acrylonitrile and the like.

  The bifunctional oligomer having two (meth) acryloyl groups in one molecule has a solubility in water at 25 ° C. of 10% by mass or less based on the total amount of water and the bifunctional oligomer, and has a weight average molecular weight. What is 300 or more is preferable. Such a component is easily absorbed in the polysiloxane particles, and greatly contributes to improvement of characteristics (for example, flexibility and elasticity) of the polymer fine particles.

  The bifunctional oligomer is not particularly limited as long as it satisfies the above characteristics. For example, polyethylene glycol di (meth) acrylate; polypropylene glycol di (meth) acrylate such as propylene glycol di (meth) acrylate; tripropylene glycol Di (meth) acrylate; polytetramethylene glycol di (meth) acrylate; neopentyl glycol di (meth) acrylate; 1,3-butylene glycol di (meth) acrylate; 2,2-bis [4- (methacryloxyethoxy) 2,2-bis [4- (methacryloxypolyethoxy) phenyl] propanedi (meth) acrylate such as phenyl] propanedi (meth) acrylate; 2,2-hydrogenated bis [4- (acryloxypolyethoxy) phenyl] propanedi Meth) EO modified di (meth) acrylate of bisphenol A, such as acrylate, isocyanuric acid EO-modified di (meth) acrylate.

  Examples of the bifunctional oligomer having the above structure include NK ester series “9PG”, “APG-200”, “APG-400”, “APG-700”, “BPE-100” manufactured by Shin-Nakamura Chemical Co., Ltd. , “BPE-200”, “BPE-500”, etc. “KAYARAD HX-220”, “KAYARAD HX-620” manufactured by Nippon Kayaku Co., Ltd., “Light Acrylate PTMGA-250” manufactured by Kyoeisha Chemical Co., Ltd. Or the like. In addition to these, “KAYARAD MANDA” and “KAYARAD R-167” manufactured by Nippon Kayaku Co., Ltd. are also preferably used.

  These polymerizable components may be used alone or in combination of two or more. When the polymerizable component is absorbed by the polysiloxane particles, a hydrophobic radical-polymerizable vinyl monomer is used in order to form a stable emulsion in advance by emulsifying and dispersing the polymerizable component to form an emulsion. It is preferable.

  In addition to the polymerizable component, a crosslinkable monomer may be used. In this case, it is easy to adjust the mechanical properties of the resulting polymer fine particles. The crosslinkable monomer is not particularly limited. For example, divinylbenzene, 1,6-hexanediol di (meth) acrylate, neopentylglycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylol Methanetri (meth) acrylate, tetramethylolpropanetetra (meth) acrylate, dipentaerythritol hexaacrylate, diallyl phthalate, ethylene oxide modified trimethylolpropane tri (meth) acrylate and its isomers, triallyl isocyanurate and its derivatives, etc. Is mentioned. These may be used alone or in combination of two or more.

  The polymerizable component may contain the hydrolyzable silicon compound described above. As the hydrolyzable silicon compound, those having a vinyl group and those not having a vinyl group can be used. However, when polysiloxane particles having no vinyl group are used as seed particles, the polymerizability can be increased. It is necessary to add a hydrolyzable silicon compound having a vinyl group to the component.

  The blending ratio of the polymerizable component is not particularly limited and may be appropriately set according to desired characteristics. For example, the blending amount of the bifunctional oligomer is 100% by mass of the polymerizable component (that is, 2 The total amount of the functional oligomer and the above-mentioned radical polymerizable vinyl monomer) is preferably 20% by mass or more, more preferably 30% by mass or more, and further preferably 40% by mass or more. When the amount of the bifunctional oligomer is within the above range, it is easy to adjust the compression deformation recovery rate of the polymer fine particles obtained. All the polymerizable components may be the above bifunctional oligomers.

  Further, the component derived from the bifunctional oligomer in the obtained polymer fine particles is preferably 10% by mass or more, more preferably 20% by mass or more, still more preferably 30% by mass or more, and 99% by mass or less. Preferably, it is 95 mass% or less, more preferably 90 mass% or less.

  The method for producing the polysiloxane particles includes: [A] a method for producing seed particles (polysiloxane having a vinyl group) by hydrolyzing and condensing the hydrolyzable silicon compound having a vinyl group, and [B] a vinyl group. Hydrolyzable silicon compound having no hydrolyzate is hydrolyzed / condensed to produce seed particles (1) (polysiloxane having no vinyl group), and then hydrolyzable having seed particles (1) and a vinyl group. A method of producing seed particles (2) (polysiloxane having a vinyl group) by hydrolyzing and condensing with a silicon compound, and [C] hydrolyzing and condensing a hydrolyzable silicon compound having no vinyl group. A seed particle (1) (polysiloxane having no vinyl group) is prepared, and the seed particle (1) absorbs a hydrolyzable silicon compound having a vinyl group and a polymerizable component described later, Any of the methods for producing seed particles (2) (polysiloxane having a vinyl group) by hydrolyzing and condensing the polysiloxane in the seed particles (1) and a hydrolyzable silicon compound having a vinyl group. Can also be adopted.

  The polymer fine particles may be an absorption step in which the above-mentioned polymerizable component is added to the polysiloxane particles in a state of being emulsified and dispersed in water with polysiloxane particles having a vinyl group, or a polysiloxane having no vinyl group. Absorption to be absorbed in addition to the polysiloxane particles by emulsifying and dispersing the polymerizable component essentially comprising the polymerizable component and a polymerizable monomer having a vinyl group and a hydrolyzable silyl group in water. And a polymerization step of radical polymerization of the polymerizable component absorbed in the polysiloxane particles in the absorption step.

  The absorption step is not particularly limited as long as it proceeds in a state where the polymerizable component is present in the presence of the polysiloxane particles. In the absorption step, the polymerizable component is absorbed in the structure of the polysiloxane particles. The concentration of the polysiloxane particles and the polymerizable component is increased so that the absorption step proceeds promptly. It is preferable to set the mixing ratio of the polysiloxane particles and the polymerizable component, the processing method / means for mixing, the temperature and time at the time of mixing, the processing method / means after mixing, etc., and carry out under the conditions.

  The addition amount of the polymerizable component in the absorption step is preferably 0.01 to 100 times by mass with respect to the mass of the silicon compound used as the raw material for the polysiloxane particles. More preferably, it is 0.5-30 times, More preferably, it is 1-15 times. If the amount added is less than the above range, the amount of the polymerizable component of the polysiloxane particles is reduced, and it may be difficult to obtain polymer fine particles having the above-mentioned mechanical properties. , When the added polymerizable component tends to be difficult to completely absorb in the polysiloxane particles, and unabsorbed polymerizable components remain, so that aggregation between particles tends to occur in the subsequent polymerization stage. There is.

  For mixing the polymerizable component and the polysiloxane particles, the polymerizable component may be added to a solvent in which the polysiloxane particles are dispersed, or the polysiloxane particles may be added to a solvent containing the polymerizable component. Among them, it is preferable to add a polymerizable component in a solvent in which polysiloxane particles are dispersed in advance as in the former, and further, polysiloxane particles are obtained from a polysiloxane particle dispersion obtained by synthesizing polysiloxane particles. It is preferable to add a polymerizable component to the dispersion without taking out the solution because the process is not complicated and the productivity is excellent.

  In the above absorption step, the timing of adding the polymerizable component is not particularly limited, and the polymerizable component may be added all at once, may be added in several times, or fed at an arbitrary rate. May be. In addition, when adding the polymerizable component, the polymerizable component may be added alone or a solution of the polymerizable component may be added, but the polymerizable component is preliminarily emulsified and dispersed with an emulsifier in the polysiloxane particles. It is preferable to add it because the absorption to the polysiloxane particles is performed more efficiently.

  The emulsifier is not particularly limited. For example, an anionic surfactant, a cationic surfactant, a nonionic surfactant, an amphoteric surfactant, a polymer surfactant, and one or more polymerizable molecules in the molecule. Examples include polymerizable surfactants having a carbon-carbon unsaturated bond. Among these, anionic surfactants and nonionic surfactants are preferable because they can stabilize the dispersion state of polysiloxane particles, polysiloxane particles that have absorbed a polymerizable component, and polymer fine particles. These emulsifiers may be used alone or in combination of two or more.

  Although it does not specifically limit as said anionic surfactant, Specifically, Alkali metal alkyl sulfates, such as sodium dodecyl sulfate and potassium dodecyl sulfate; Ammonium alkyl sulfates, such as ammonium dodecyl sulfate; Sodium dodecyl Polyglycol ether sulfate, sodium sulfosinoate, alkali metal salts of sulfonated paraffin; alkyl sulfonates such as ammonium salt of sulfonated paraffin; fatty acid salts such as sodium laurate, triethanolamine oleate, triethanolamine abiate, Alkyl aryl sulfones such as sodium dodecylbenzene sulfonate and alkali metal sulfate of alkali phenol hydroxyethylene Over preparative like; higher alkyl naphthalene sulfonate, naphthalenesulfonic acid formalin condensates, dialkyl sulfosuccinate, polyoxyethylene alkyl sulfate salts, and polyoxyethylene alkylaryl sulfate salts.

  The cationic surfactant is not particularly limited, and examples thereof include amine salts, quaternary ammonium salts, oxyethylene addition type ammonium hydrochlorides, and the like, and specifically, trimethylalkylammonium hydrochloride. Dimethyldialkylammonium hydrochloride, monoalkylamine acetate, alkylmethyldipolyoxyethyleneammonium hydrochloride, and the like. The alkyl group contained in these cationic surfactants is preferably a saturated aliphatic hydrocarbon group or unsaturated aliphatic hydrocarbon group having 4 to 26 carbon atoms, such as octyl group, dodecyl group, tetradecyl group. Group, hexadecyl group, octadecyl group, behenyl group, oleyl group, stearyl group and the like.

  The nonionic surfactant is not particularly limited, and specific examples include polyoxyethylene alkyl ether, polyoxyethylene alkyl aryl ether, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, and monoglycerol glycerol. Examples thereof include fatty acid monoglycerides such as laurate; polyoxyethyleneoxypropylene copolymers, condensation products of ethylene oxide and fatty acid amines, amides or acids.

  Examples of the amphoteric surfactants include amino acid type amphoteric surfactants and betaine type amphoteric surfactants. Examples thereof include alkyldi (aminoethyl) glycine, alkylpolyaminoethylglycine hydrochloride, and 2-alkyl-N-carboxyethyl. -N-hydroxyethylimidazolinium betaine, N-tetradecyl-N, N-betaine type amphoteric surfactants (for example, “Amogen K” manufactured by Daiichi Kogyo Seiyaku Co., Ltd.).

  Specific examples of the polymeric surfactant include polyvinyl alcohol, sodium poly (meth) acrylate, potassium poly (meth) acrylate, ammonium poly (meth) acrylate, polyhydroxyethyl (meth) acrylate, poly Two or more kinds of copolymers of hydroxypropyl (meth) acrylate, polyvinyl pyrrolidone and polymerizable monomers which are constituent units of these polymers, copolymers with other monomers, correlation transfer of crown ethers A catalyst etc. are mentioned.

  The polymerizable surfactant is not particularly limited, but examples thereof include sodium propenyl-2-ethylhexylbenzenesulfosuccinate, sulfate of polyoxyethylene (meth) acrylate, polyoxyethylene alkylpropenyl ether ammonium sulfate. Anionic polymerizable surfactants such as salts, phosphoric acid esters of (meth) acrylic acid polyoxyethylene esters; polyoxyethylene alkylbenzene ether (meth) acrylic acid esters, polyoxyethylene alkyl ether (meth) acrylic acid esters, etc. Nonionic polymerizable surfactants and the like can be mentioned.

  The usage-amount of the said emulsifier is not specifically limited, Specifically, it is preferable that it is 0.01-10 mass% with respect to the total mass of the said polymeric component, More preferably, it is 0.05-8. It is 1 mass%, More preferably, it is 1-5 mass%. When the amount of the emulsifier used is less than 0.01% by mass, an emulsion dispersion of a stable polymerizable component may not be obtained. When the amount exceeds 10% by mass, emulsion polymerization or the like occurs as a side reaction. There is a risk of it. About the said emulsification dispersion | distribution, it is preferable to usually make the said polymeric component into an emulsion state in water using a homomixer, an ultrasonic homogenizer, etc. with an emulsifier.

  Moreover, when emulsifying and dispersing the polymerizable component with an emulsifier, it is preferable to use water or a water-soluble organic solvent 0.3 to 10 times the mass of the polymerizable component. Examples of the water-soluble organic solvent include alcohols such as methanol, ethanol, isopropanol, n-butanol, isobutanol, sec-butanol, t-butanol, pentanol, ethylene glycol, propylene glycol, 1,4-butanediol; acetone And ketones such as methyl ethyl ketone; esters such as ethyl acetate;

  The absorption step is preferably performed in the temperature range of 0 to 60 ° C. with stirring for 5 minutes to 720 minutes. These conditions may be set as appropriate depending on the type of polysiloxane particles and polymerizable components used, and these conditions may be used alone or in combination of two or more.

  In the above absorption process, whether or not the polymerizable component has been absorbed is determined by observing the particles with a microscope before adding the polymerizable component and after completion of the absorption step, and the particle size is increased by absorption of the polymerizable component. This can be easily determined.

  After completion of the absorption step, it is preferable to dilute by adding water so that the particle concentration in the dispersion of the polysiloxane particles having absorbed the polymerizable component is 40% by mass or less with respect to the total amount of the dispersion. More preferably, it is 30 mass% or less, More preferably, it is 20 mass% or less. This is because if the particle concentration of the dispersion is too high, it may be difficult to control the temperature due to heat generated by the polymerization reaction in the subsequent polymerization step. At this time, the above-described surfactant may be additionally added to the particles in order to improve the dispersion stability.

  In the polymerization step, the method for radical polymerization is not particularly limited, and examples thereof include a method using a radical polymerization initiator, a method of irradiating ultraviolet rays and radiation, and a method of applying heat. The radical polymerization initiator is not particularly limited, but examples thereof include persulfates such as potassium persulfate, hydrogen peroxide, peracetic acid, benzoyl peroxide, lauroyl peroxide, orthochlorobenzoyl peroxide, orthomethoxybenzoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, t-butylperoxy-2-ethylhexanoate, di-t-butyl peroxide, benzoyl peroxide, 1,1-bis (t-butylperoxy)- Peroxide initiators such as 3,3,5-trimethylcyclohexane and t-butyl hydroperoxide; azobisisobutyronitrile, azobiscyclohexacarbonitrile, azobis (2,4-dimethylvaleronitrile), 2'-azobisisobutyronitrile, 2,2'-azobis (2-amidino Lopan) dihydrochloride, 4,4'-azobis (4-cyanopentanoic acid), 2,2'-azobis- (2-methylbutyronitrile), 2,2'-azobisisobutyronitrile, 2 Preferred examples include azo compounds such as 2,2′-azobis (2,4-dimethylvaleronitrile). These radical polymerization initiators may be used alone or in combination of two or more.

  The amount of the radical polymerization initiator used is preferably 0.001% by mass to 20% by mass, more preferably 0.01% by mass to 10% by mass, more preferably the total mass of the polymerizable component. More preferably, it is 0.1 mass%-5 mass%. When the usage-amount of the said radical polymerization initiator is less than 0.001 mass%, the polymerization degree of a polymerizable component may not rise. The method of charging the radical polymerization initiator into the solvent is not particularly limited, and a method in which the entire amount is initially charged (before the reaction is started) (a mode in which the radical polymerization initiator is emulsified and dispersed together with the polymerizable component, the polymerizable component is A mode in which a radical polymerization initiator is charged after absorption); a method in which a part is initially charged and the rest is continuously fed, a pulse is intermittently added, or a combination of these is conventionally used Any known method can be employed.

  The reaction temperature for the radical polymerization is preferably 40 to 100 ° C, more preferably 50 to 80 ° C. If the reaction temperature is too low, the degree of polymerization does not increase sufficiently and the mechanical properties of the polymer fine particles tend to be difficult to obtain. On the other hand, if the reaction temperature is too high, aggregation between particles occurs during the polymerization. Tends to occur. The reaction time for the radical polymerization may be appropriately changed according to the type of polymerization initiator used, but is usually preferably 5 to 600 minutes, more preferably 10 to 300 minutes. When the reaction time is too short, the degree of polymerization may not be sufficiently increased, and when the reaction time is too long, aggregation tends to occur between particles.

  Next, a method for producing coated fine particles according to the present invention will be described. The production method according to the present invention is a production method of coated fine particles having a polymer coating layer on the surface of core fine particles made of an organic material or an organic-inorganic composite material, in an aqueous medium in which the core particles are dispersed. The polymer coating layer is characterized by being formed by ring-opening and / or polycondensation reaction in the presence of a surfactant.

  By adopting such a production method, a uniform polymer coating layer can be formed around the core fine particles. Further, when the compound represented by the formula (1) is used as the surfactant, the surfactant is contained in the insoluble reaction product derived from the compound (A) and / or the compound (B). The polymer coating layer contained can be formed on the surface of the core fine particles. That is, the production method of the present invention refers to an intermolecular force such as a hydrophobic interaction acting between the core fine particles and the surfactant, and further between the surfactant and the compound (A) and / or the compound (B). Is used to form a polymer coating layer for coating the core fine particles. That is, the surfactant added to the aqueous medium is aggregated on the surface of the core fine particles, whereby the aggregation of the core fine particles is suppressed and the core fine particles are dispersed in the aqueous medium. Next, the compound (A) (initial condensing compound) and / or the compound (B) (epoxy compound) is added thereto, and these are ring-opened around the surfactant, that is, surrounding the core fine particles. / Or polycondensation reaction proceeds. As a result, a uniform polymer coating layer is formed on the surface of the core fine particles.

  In addition, although a chemical bond is formed between the compound (A) or the epoxy compound and the surfactant by the ring-opening and / or polycondensation reaction, a polymer coating layer is formed (in the above formula (1)). In the case of using the surfactant represented), only the intermolecular force such as hydrophobic interaction or hydrogen bond acts between the core fine particle and the polymer coating layer. No chemical bond is formed between the polymer coating layer and the polymer coating layer.

  The polymer coating layer according to the present invention is formed in an aqueous medium, and the aqueous medium includes a mixed solvent of water and an organic solvent in addition to a case where only water is used as a reaction solvent. The organic solvent is preferably hydrophilic, for example, alcohols such as methanol, ethanol, isopropyl alcohol, n-propyl alcohol, allyl alcohol; ethylene glycol, propylene glycol, butylene glycol, hexylene glycol, pentanediol, hexane Glycols such as diol, heptanediol, dipropylene glycol; ketones such as acetone, methyl ethyl ketone, methyl propyl ketone; esters such as methyl formate, ethyl formate, methyl acetate, methyl acetoacetate; diethylene glycol monomethyl ether, diethylene glycol monoethyl ether , Diethylene glycol dimethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether How ethers, and the like. These may be used alone or in combination of two or more. In addition, when the above-mentioned initial condensation compound is difficult to dissolve in water, it is preferable to use the above-mentioned mixed solvent. In this case, it is preferable that the compounding quantity of the organic solvent with respect to water is 50 mass% or less, More preferably, it is 40 mass% or less.

  Furthermore, an organic solvent other than the hydrophilic organic solvent (other organic solvent) may be used. Specifically, dioxane, hexane, cyclopentane, pentane, isopentane, octane, benzene, toluene, xylene, ethylbenzene, Examples include petroleum ether, terpene, castor oil, soybean oil, paraffin, and kerosene. When these other organic solvents are used, the amount used is preferably 30% by mass or less, more preferably 25% by mass or less, and still more preferably 20% by mass in the mixed solvent comprising the water-hydrophilic organic solvent. % Or less.

  The concentration of the core fine particles in the aqueous medium is preferably 1% by mass or more, more preferably 2% by mass or more, and preferably 60% by mass or less, more preferably 50% by mass or less. If the amount of the core fine particles is too large, the core fine particles may be aggregated in the coating step. If the amount is too small, the polymer component derived from the compound (A) and the compound (B) not containing the core fine particles in the medium is precipitated. There is a risk.

  The amount of the surfactant added is preferably 1% by mass or more, more preferably 3% by mass or more, still more preferably 5% by mass or more, and 50% by mass or less based on the core fine particles. More preferably, it is 30 mass% or less, More preferably, it is 25 mass% or less. If the blending amount of the surfactant is too small, the dispersion state of the core fine particles cannot be maintained sufficiently stably, and the core fine particles may be aggregated. On the other hand, when there are too many compounding quantities, the viscosity of the whole reaction system will rise rapidly, and there exists a possibility that stirring may become difficult. In addition, from the viewpoint of the physical properties of the resulting coated fine particles, if the blending amount of the surfactant is within the above range, an appropriate flexibility can be imparted to the polymer coating layer. Strength can be improved.

  In the production method of the present invention, the method for dispersing the core fine particles in the aqueous medium is not limited, and a conventionally known dispersion method can be employed. For example, a mixture containing an aqueous medium, core fine particles, and a surfactant is mechanically processed with an ultrasonic disperser, a disper, a homomixer (made by Special Machinery Co., Ltd.), and a homogenizer (made by Nippon Seiki Co., Ltd.) A method of vigorously stirring and dispersing is preferred.

  The surfactant may be dissolved in the aqueous medium before the core fine particles are dispersed in the aqueous medium, or may be dissolved at the same time as or after the dispersion. The timing is not particularly limited.

  Next, the initial condensation compound is added to the aqueous medium in which the core fine particles are dispersed. The amount of the initial condensation compound added is not limited, but is preferably 0.1 parts by mass or more, more preferably 0.2 parts by mass or more, and still more preferably 0.3 parts by mass with respect to 1 part by mass of the surfactant. It is preferably at least 10 parts by mass, more preferably at most 5 parts by mass, and even more preferably at most 3 parts by mass. The thickness of the polymer coating layer can be easily controlled by adjusting the addition amount of the initial condensation compound. If the addition amount of the initial condensation compound is too small, it is difficult to form a polymer coating layer having a sufficient thickness. If the addition amount is too large, the component composition of the polymer coating layer is largely biased, and the polymer coating layer is formed. In some cases, the strength of the metal is reduced, or the adhesion to the metal is poor.

  The method for adding the initial condensation compound to the aqueous medium is not limited, and may be batch addition or sequential addition (continuous addition and / or intermittent addition).

  In the production method of the present invention, the temperature at which the polymer coating layer is formed (the temperature of the aqueous medium in which the core fine particles are dispersed and the water-soluble compound is added) is preferably 25 to 85 ° C., more preferably 30 to It is 70 degreeC, More preferably, it is 35-60 degreeC.

  Moreover, it is preferable that the pH of the reaction liquid at the time of polymer coating layer formation is 2-13, More preferably, it is 3-12, More preferably, it is 4-11. When the pH of the reaction solution is within the above range, the core fine particles are hardly aggregated and the reaction rate can be easily controlled. The reaction time is preferably 10 to 480 minutes, more preferably 30 to 360 minutes, and still more preferably 60 to 300 minutes.

  An aging period may be provided after the formation of the polymer coating layer. The temperature during aging is not particularly limited, but is preferably 200 ° C. or lower, for example. There is no limitation also in aging time, Preferably it is 1 to 5 hours, More preferably, it is 1 to 3 hours. The pH of the solution during aging is preferably in the range of 2-13. The aging may be performed under pressure. In this case, the pressure is not particularly limited, but is preferably in the range of, for example, normal pressure to 20 atmospheric pressure.

  In addition, when an epoxy resin is contained in the polymer coating layer, the addition amount of the epoxy compound is not particularly limited, but is preferably 0.5 parts by mass or more and 10 parts by mass or less with respect to 1 part by mass of the core fine particles. . By adjusting the addition amount of the epoxy compound, the thickness of the formed epoxy resin layer (polymer coating layer) can be easily controlled. In addition, when there are too few addition amounts, the effect of an adhesive improvement with the metal by formation of an epoxy resin layer may be difficult to be acquired. Even if the addition amount exceeds 10 parts by mass, there is no particular problem, but no improvement in adhesion with the metal corresponding to the addition amount is recognized, and the economy is inferior. Therefore, a more preferable upper limit is 5 parts by mass, and further preferably 3 parts by mass.

  The temperature at which the epoxy resin layer is formed is preferably the same as the polymer coating layer forming temperature when the compound (A) is employed.

  In the production method of the present invention, an adjustment liquid in which coated fine particles are dispersed in an aqueous medium is obtained by the above-described polymer coating layer formation and aging performed as necessary.

  In the production method of the present invention, if necessary, a surfactant and the compound (A) and / or the compound (B) are further added to the adjustment solution to perform a ring-opening and / or polycondensation reaction. Also good. As a result, a similar polymer coating layer is formed on the surface of the previously formed polymer coating layer, and as a result, coated fine particles having a layered polymer coating layer are obtained. The coated polymer provided with a plurality of polymer coating layers can further improve, for example, the physical properties obtained with a single polymer coating layer, and the inner and outer layers of the polymer coating layer. Thus, different physical properties can be developed by changing the composition of the constituent components. Specifically, it is possible to obtain an effect that physical properties such as mechanical properties and hydrophilicity can be easily introduced while having the original performance of the polymer coating layer.

  After the formation of the polymer coating layer, the coated fine particles may be isolated as necessary. For example, after the coated fine particles are adjusted, the coated fine particles may be separated from the aqueous medium by suction filtration or natural filtration.

  Further, in order to obtain coated fine particles having a sharp particle size distribution, the coated fine particles after isolation may be classified. For classification, for example, a wet classification method (wet classification) is preferably adopted. The wet classification is a method of classifying the coated fine particles with respect to the adjustment liquid in which the coated fine particles are dispersed. Since classification is performed on the adjustment liquid, wet classification is performed. The wet classification is a method in which the above-mentioned adjustment liquid is classified as it is or diluted with an arbitrary aqueous medium, and the coated fine particles in the adjustment liquid are classified so as to have a desired particle size and particle size distribution. is there. The wet classification can be performed by, for example, a method or an apparatus using a method such as a sieve type (filter type), a centrifugal sedimentation type, or a natural sedimentation type. For coated fine particles having a relatively large particle size, the sieve type can be used effectively.

  It is also preferable to wash the obtained coated fine particles in order to remove impurities and improve product quality.

  Hereinafter, characteristics and various physical properties of the coated fine particles of the present invention will be described.

  The coated fine particles of the present invention include those in which the surface of the core fine particles is exposed in part of the coated fine particles, in addition to those in which the entire surface of the core fine particles is covered with the polymer coating layer. However, if there are too many exposed portions of the core fine particles, the adhesion to the metal is lowered, and it may be difficult to form a uniform conductor layer (described later) on the surface of the fine particles. Such a defect causes a conduction failure when used as conductive fine particles, or causes a decrease in conduction reliability. Therefore, the coverage of the core fine particle surface by the polymer coating layer is preferably 40% or more, more preferably 50% or more, and further preferably 55% or more. Of course, 100% is most preferable.

  In the coated fine particles of the present invention, the form of the component derived from the surfactant may be composed of one molecule of the surfactant, or two or more molecules such as a dimer or a trimer are collected. It may be a thing and is not limited. Among these, only 1 type may be contained in the polymer coating layer, and 2 or more types may be contained in the polymer coating layer.

  The content ratio of the component derived from the surfactant is not limited, but is preferably 5% by mass or more, more preferably 10% or more, and further preferably 15% by mass with respect to the entire polymer coating layer. It is above, and it is preferable that it is 80 mass% or less, More preferably, it is 75% or less, More preferably, it is 70 mass%. When the content ratio is small, the flexibility may be reduced, resulting in a polymer coating layer having low mechanical strength. When the content ratio is too large, the adhesion with the metal may be decreased.

  Similarly, various amino resins (urea-based resins, melamine resins, guanamines) may be used as the constituent components derived from the initial condensation compound (compound (A)), which is a constituent component of the polymer coating layer in the coated fine particles of the present invention. Of these, only one type may be contained in the polymer coating layer, or two or more types may be contained in the polymer coating layer.

  The content ratio of the component derived from the compound (A) and / or the compound (B) is preferably 20% by mass or more, more preferably 25% by mass or more, further preferably, with respect to the entire polymer coating layer. It is 30 mass% or more, and it is preferable that it is 95 mass% or less, More preferably, it is 90 mass% or less, More preferably, it is 85 mass% or less. When the content ratio is less than the above range, the adhesion to the metal may be inferior, and when it exceeds the above range, the coated fine particles may have poor flexibility and low mechanical strength.

  The polymer coating layer in the coated fine particles of the present invention may contain other components other than the above components as long as the effects of the present invention are not impaired. Examples of the other constituent components include constituent components derived from the above-mentioned other compounds that can be used in combination with the above-described surfactant, specifically, constituent components derived from polyvinyl alcohols, and various other than the above. Components derived from surfactants, components derived from natural polymer dispersants such as gelatin and gum arabic, components derived from synthetic polymer dispersants such as styrene / maleic acid copolymers and their salts, etc. Is mentioned.

  The shape of the coated fine particles of the present invention is not particularly limited, and examples thereof include a spherical shape, a needle shape, a plate shape, a scale shape, a pulverized shape, an uneven shape, an eyebrows shape, and a confetti shape.

The coated fine particles of the present invention having the above configuration have a compressive elastic modulus (10% K value) of 50 N / mm ² or more when the diameter of the coated fine particles is displaced by 10%, and a compression deformation recovery rate of 5% or more. Preferably there is. Preferably, the compression modulus of 1000 N / mm ² or more, more preferably 2450N / mm ² or more, the compressive deformation recovery factor of 10% or more, more preferably 15% or more. Here, the compression elastic modulus (10% K value) indicates the flexibility of the coated fine particles, and the compression deformation recovery rate indicates the elasticity of the coated fine particles. The upper limit is not particularly limited, but is preferably compression modulus is 20000N / mm ² or less, more preferably 15000 N / mm ^2, more preferably not more than 10000 N / mm ^2. If the compression modulus is too small, the coated fine particles are too flexible, and when used as a gap holding material between various substrates, it may be difficult to maintain a uniform gap distance. If the fine particles are too hard and used as a gap retaining material, the substrate surface may be damaged.

  The compression deformation recovery rate is an index of the elasticity of the coated fine particles. When a constant load is applied to the coated fine particles and the load is removed, the amount of change in the particle diameter of the coated fine particles before and after the load is applied. Desired. The compression deformation recovery rate of the coated fine particles of the present invention is preferably 5% or more, more preferably 10% or more, and further preferably 15% or more. Needless to say, it is preferable that the upper limit of the compression deformation recovery rate is 100%, that is, it is preferable that the particle diameter of the coated fine particles does not change before and after loading.

  Further, the coated fine particles of the present invention preferably have a displacement amount of 1% or more with respect to the diameter of the coated fine particles of 5% or more. The displacement amount at the time of 1 g load indicates the ease of deformation of the coated fine particles of the present invention, particularly the ease of deformation at the time of low load load. The displacement at the time of 1 g load is preferably 5% or more, more preferably 10% or more, further preferably 20% or more, preferably 85% or less, more preferably 80% or less. More preferably, it is 75% or less. Similar to the compression deformation recovery rate, when the displacement amount at the time of 1 g load is not included in the above range, it tends to be difficult to keep the gap distance uniform when used as a gap holding material between various substrates. is there.

  The average particle diameter of the coated fine particles of the present invention is not particularly limited, but is preferably 1.0 μm or more, more preferably 2.0 μm or more, preferably 100 μm or less, more preferably 70 μm or less. More preferably, it is 50 μm or less. If the particle size of the coated fine particles is too small, there is a risk of polymer fine particles consisting only of an initial condensate that does not enclose the core fine particles. If the particle size is too large, the physical properties normally required as coated fine particles May not be able to be held.

  The sharpness of the particle size distribution of the coated fine particles of the present invention is not particularly limited. For example, the particle diameter variation coefficient (Cv value) is preferably 10% or less, more preferably 5% or less, and still more preferably 4%. It is as follows. When the coefficient of variation (Cv value) is within the above range, when used as a gap holding material for making gaps between various substrates uniform, an advantageous effect of keeping the gap distance uniform can be exhibited. it can. On the other hand, when the variation coefficient (Cv value) exceeds the above range, the uniformity of the gap distance may not be sufficiently maintained when used as a gap holding material.

  The above characteristics (elasticity and compression modulus), particle diameter, and coefficient of variation (that is, sharpness of particle size distribution) of the coated fine particles of the present invention greatly depend on the characteristics (particle diameter and particle size distribution) of the core fine particles. To do. Therefore, the coated fine particles having desired characteristics can be obtained by appropriately adjusting the conditions during the production of the core fine particles.

  The thickness of the polymer film of the present invention is not limited, but is preferably 0.001 μm or more, more preferably 0.005 μm or more, still more preferably 0.008 μm or more, and preferably 10 μm or less. . If the thickness of the polymer coating is too thin, the adhesion to the metal may be reduced, and the strength of the coated fine particles may be reduced. On the other hand, if the thickness is too thick, the ratio of the core fine particles to the coated fine particles Therefore, flexibility and elasticity may be insufficient.

  Next, the conductive fine particles according to the present invention will be described.

  The conductive fine particles according to the present invention are those in which a conductor layer is formed on the surface of the coated fine particles according to the present invention. The conductor layer may be formed on at least a part of the surface of the coated fine particles.

  Although the metal which comprises the said conductor layer is not specifically limited, For example, nickel, gold | metal | money, silver, copper, indium, these alloys etc. are mentioned. Among these, nickel, gold, and indium are preferable because of high conductivity. The thickness of the conductor layer is not particularly limited as long as there is sufficient conduction, but is preferably 0.01 μm or more, more preferably 0.02 μm or more, and preferably 5.0 μm or less. Preferably it is 2.0 micrometers or less. If the thickness of the conductor layer is too thin, the conductivity may be insufficient. On the other hand, if it is too thick, the conductor layer may be easily peeled off due to the difference in thermal expansion coefficient between the conductor layer and the polymer coating layer. There is. The conductor layer may be one layer or two or more layers, and in the case of two or more layers, different types of metals may be laminated.

  The method for forming the conductor layer on the surface of the coated fine particles of the present invention is not particularly limited, and conventionally known methods can be employed. For example, an electroless plating (chemical plating) method, a coating method, a PVD (vacuum deposition, sputtering, ion plating, etc.) method and the like can be mentioned. Among them, the electroless plating method can easily form a conductor layer. Therefore, it is preferable.

  The electroless plating method usually comprises an etching process, an activation process, and an electroless plating process. Here, the etching step is a step of forming irregularities on the surface of the coated resin fine particles to improve the adhesion of the electroless plating layer, but the coated fine particles according to the present invention have good adhesion to the metal. Since the polymer coating layer is provided, the etching process is not an essential process and can be omitted. In the etching step, an alkaline aqueous solution such as a caustic soda aqueous solution or an aqueous acid solution such as hydrochloric acid, sulfuric acid, or chromic anhydride may be used as the etching solution. The subsequent activation process and electroless plating process may be performed according to a conventionally known method.

  Since the conductive particles of the present invention use the coated fine particles of the present invention as a base particle, the hardness required to keep a gap distance between a pair of electrically connected electrode substrates constant and It has a compression deformation recovery rate, and hardly damages the electrode physically. For this reason, it is easy to keep the gap distance between a pair of electrode substrates constant, the conductor layer is peeled off by pressurization, a short between electrodes that should not be electrically connected, and between electrodes that should be electrically connected Can prevent poor contact.

  The conductive particles of the present invention thus obtained have the same mechanical properties (hardness and breaking strength) as the coated fine particles of the present invention. Therefore, it is particularly useful as an electrical connection material for electronics such as liquid crystal display boards, LSIs, and printed wiring boards.

  Hereinafter, the present invention will be described in detail based on examples. However, the following examples are not intended to limit the present invention, and all modifications made without departing from the spirit of the preceding and following descriptions are included in the technical scope of the present invention. The measuring method is as follows.

[Measurement of film thickness of polymer coating layer]
Using Coulter Multisizer II (manufactured by Beckman Coulter, Inc.), the particle diameter before and after the coating layer application was measured, and the difference in particle diameter before and after the coating layer application was divided by 2 to calculate the thickness of the coating layer.

  Table 1 also shows the particle diameter of the coated fine particles and the coefficient of variation of the particle diameter.

[Evaluation of surface properties of polymer coating layer]
The surface state of the particles before and after the formation of the polymer coating layer was observed with a scanning electron microscope (SEM, S3500N, manufactured by Hitachi, Ltd.) and evaluated in three stages according to the following criteria.
[Evaluation criteria]
1: The polymer coating layer on the surface of the core particle is very thin, or the polymer coating layer is not formed and exists as single particles.
2: The core particle surface is covered with a uniform polymer coating layer and exists as single particles.
3: The core particle surface is covered with a large amount of resin, and the particles are adhered to each other by the resin.

[Plating adhesion]
10 g of the coated fine particles obtained by the following production examples were subjected to electroless nickel plating treatment, and the plated state of the treated particle surface was observed with an electron microscope and evaluated according to the following criteria.
[Evaluation criteria]
○ (good): The particle surface is uniformly covered with a nickel coating layer.
X (Inferior): A nickel coating layer is not formed on the particle surface.

[Average particle size and coefficient of variation of particle size]
The average particle size of the polysiloxane particles and polymer fine particles was determined by measuring the particle size of 30000 particles using a Coulter Multisizer (manufactured by Beckman Coulter, Inc.).

  The variation coefficient of the particle diameter was determined according to the following formula.

[10% compression modulus (10% K value: hardness)]
A circular plate indenter with a diameter of 50 μm per sample particle spread on a sample table (material: SKS flat plate) at room temperature (25 ° C.) by a Shimadzu micro-compression tester (manufactured by Shimadzu Corporation, “MCTW-500”) (Material: diamond) Using a load at a constant load speed (2.275 mN / sec) toward the center of the particle, the load when the particle is deformed until the compression displacement becomes 10% of the particle diameter And the amount of displacement (mm) is measured. The measured compression load, particle compression displacement, and particle radius are expressed as follows:

(Where E: compression elastic modulus (N / mm ² ), F: compression load (N), S: compression displacement (mm), R: radius of particle (mm)) calculate. This operation is performed for three different particles, and the average value is taken as the 10% compression modulus of the polymer fine particles.

[Compression deformation recovery rate (recovery rate)]
Using a micro-compression tester (manufactured by Shimadzu Corporation, “MCTW-500”), measure the relationship between the load value and compression displacement when the load is reduced after compressing the sample particles to the reverse load of 9.8 mN. Displacement to the reversal point (L1) when the end point when removing the load is the origin load value of 0.098 mN and the compression speed at the load and the unloading is 1.486 mN / sec. And the ratio (L1 / L2) [%] to the displacement (L2) from the reversal point to the point where the origin load value is taken.

[Displacement at 1 g load (compressibility)]
A circular plate indenter (material: 50 μm in diameter) for one sample particle spread on a sample table (material: SKS flat plate) at room temperature (25 ° C.) by a micro compression tester (manufactured by Shimadzu Corporation, “MCTW-500”) : Diamond), a load is applied in the center direction of the particle at a constant load speed, and the amount of particle displacement (L3) at the time of 0.098 mN (1 g load) load is compared with the particle diameter (D) (L3 / D) Value expressed as [%].

Synthesis Example (1) Synthesis of Initial Condensation Compound (Synthesis of Compound (a)) In a 50 ml separable flask, urea: 3 g, melamine: 7 g, 37 mass% formalin: 20 g, 25 mass% aqueous ammonia: 1.5 g The temperature was raised to 70 ° C. while charging and stirring. After maintaining at the same temperature for 15 minutes, it is cooled to room temperature, and the compound (a) is a homogeneous solution which is an initial condensation compound of melamine and urea and formaldehyde (solid content concentration 55% by mass with respect to the total amount of the uniform solution of compound (a)) Got.

Synthesis Example (2) Synthesis of Surfactant (Compound (b)) Polyethyleneimine (“Epomin SP006”, weight average molecular weight = 600, manufactured by Nippon Shokubai Co., Ltd.): 14.5 g in a 300 ml separable flask, Water: 43.5 g of initial charge, and then a 25 mass% aqueous solution of an epoxy compound (lauryl polyoxyethylene (n = 22) glycidyl ester, solubility in water: 100%) prepared in advance under stirring : 97.2 g was added dropwise over 10 minutes.

  The solution was added dropwise while keeping the liquid temperature at 25 ° C. or lower at the time of dropping, continued stirring for 30 minutes after completion of the dropping, then heated to 70 ° C., held at the same temperature for 2 hours, cooled to room temperature, and having dispersibility (B) (solid content concentration of 25% by mass relative to the total amount of the mixture) was obtained.

Synthesis Example (3) Synthesis of Core Fine Particles (Organic / Inorganic Composite Fine Particles) A solution in which 250 parts of water and 10 parts of 25% ammonia water were mixed in a four-necked flask equipped with a cooling tube, a thermometer, and a dripping port, While stirring, a solution prepared by mixing 30 parts of γ-methacryloxypropyltrimethoxysilane and 125 parts of methanol was added from the dropping port to hydrolyze and condense γ-methacryloxypropyltrimethoxysilane. Siloxane particles (inorganic particles) were prepared. One hour after the start of the reaction, 250 parts of water was added from the dropping port to dilute the polysiloxane particle dispersion. Stirring was continued for 2 hours from the start of the reaction to obtain a polysiloxane particle dispersion (average particle size: 1.83 μm, coefficient of variation: 3.17%).

  A flask different from the above four-necked flask, 0.7 part of anionic emulsifier (LA-10, manufactured by Daiichi Kogyo Seiyaku), 70 parts of water, and NK ester APG-400 (manufactured by Shin-Nakamura Chemical Co., Ltd.) 100 parts, 1,6-hexanediol dimethacrylate 20 parts, 2,2′-azobis (2,4-dimethylovaleronitrile) (“V-65” manufactured by Wako Pure Chemical Industries, Ltd.) 0.5 The parts were mixed and emulsified and dispersed for 5 minutes using a homogenizer to prepare a monomer emulsion.

  After stirring the organic-inorganic composite particle dispersion for 30 minutes, the above-mentioned monomer emulsion was added thereto in 15 seconds, and stirring was further performed for 30 minutes. At this time, the polysiloxane particles were observed with a microscope, and it was confirmed that the inorganic particles absorbed the monomer from the increase in the particle diameter. One hour after the addition of the monomer emulsion, 1000 parts of water is added to the organic-inorganic composite particle dispersion that has absorbed the monomer, and the reaction solution is heated to 75 ° C. under a nitrogen atmosphere and held for 30 minutes to perform radical polymerization. An emulsion of core fine particles was obtained (average particle size: 3.8 μm, coefficient of variation: 2.9%).

  The obtained core fine particle emulsion was filtered, washed with ethanol, and then vacuum dried at 100 ° C. for 4 hours to obtain core fine particles. The properties of the obtained core fine particles are shown in Table 1.

Synthesis Example (4) Synthesis of Polystyrene Particles In a four-necked flask equipped with a condenser, a thermometer, and a dripping port, 2 parts of polyvinylpyrrolidone (weight average molecular weight (Mw) 30,000) and 1 part of azobismethylvaleronitrile are added. While stirring a solution dissolved in 150 parts of isopropanol under a nitrogen stream, 15 parts of styrene was added thereto, and then the temperature was raised to 60 ° C. and a polymerization reaction was performed for 24 hours to obtain a polystyrene particle dispersion (average) Particle size: 5.1 μm, coefficient of variation: 7.3%).

  Polystyrene particles were separated from the obtained dispersion, washed, classified, and dried to obtain polystyrene particles (average particle size 5.1 μm, coefficient of variation 4.8%). Table 1 shows the properties of the obtained polystyrene particles.

Production Example 1
10 g of the solution of the compound (b) obtained in Synthesis Example (2) and 20 g of the core fine particles obtained in Synthesis Example (3) are placed in a 300 ml beaker, mixed with a spatula, and 50 g of water is added to the solution. The core fine particles were dispersed by applying sound waves (dispersion C1).

  The dispersion C1 was placed in a 300 ml flat bottom separable flask equipped with a stirrer, 6 g of the solution of the compound (a) was added with stirring (rotation speed 200 rpm), and the temperature was raised to 40 ° C. After maintaining at the same temperature for 2 hours (note that the pH of the reaction solution at this time is 10), 150 ml of water was added and cooled to room temperature to obtain coated fine particles D1. Table 2 shows the evaluation results of the polymer coating layer thickness and particle surface properties of the coated fine particles D1. In addition, FIGS. 3 and 4 show electron microscope (SEM) photographs of the core fine particles and the coated fine particles D1 used at this time, respectively.

  The obtained coated fine particles D1 were subjected to Ni plating by an electroless plating method, and the plating property was evaluated. The results are also shown in Table 2.

  The Ni plating was performed as follows. 10 g of the coated fine particles (D1) are dispersed in 200 g of a 1% by mass sodium hydroxide aqueous solution, stirred at 60 ° C. for 2 hours, etched, filtered and dried, and then added to a 1 g / l stannous chloride aqueous solution at room temperature. Sensitization treatment was performed by immersion for 5 minutes. The coated fine particles after the sensitization treatment are added to a catalyst solution composed of 0.1 ml / l palladium chloride aqueous solution and 0.1 ml / l hydrochloric acid while stirring, and further stirred for 5 minutes to trap palladium ions in the coated fine particles. Then, this was filtered and washed, and further immersed in a 1 g / l sodium hypophosphite aqueous solution at room temperature for 5 minutes for reduction treatment to obtain base particles having palladium supported on the surface of the coated fine particles. It was.

  Next, the base particles were added and dispersed in an aqueous glycine solution (20 g / l) heated to 65 ° C. with stirring to prepare a slurry. Under stirring of this slurry, a nickel electroless plating solution comprising a nickel sulfate aqueous solution, a sodium hypochlorite aqueous solution, and a sodium hydroxide aqueous solution was added at a rate of 5 ml / min. After the entire amount of nickel electroless plating solution was added, stirring was continued while maintaining the solution temperature at 65 ° C. until hydrogen bubbling stopped. After stopping the foaming of hydrogen, the fine particles in the system were filtered and washed, and dried with a vacuum dryer (100 ° C.) to obtain conductive fine particles having a nickel coating.

Production Example 2
Dispersion C1 was placed in a 300 ml flat bottom separable flask equipped with a stirrer, and 6 g of the solution of compound (a) was added with stirring (rotation speed 200 rpm), and the temperature was raised to 40 ° C. After maintaining at the same temperature for 3 hours, 150 ml of water was added and cooled to room temperature to obtain coated fine particles D2. Further, Ni plating was applied to the coated fine particles D2 in the same manner as in Production Example 1 above. Table 2 shows the evaluation results of the properties (polymer coating layer thickness, surface properties and plating properties) of the coated fine particles D2.

Production Example 3
5 g of the compound (b) solution obtained in Synthesis Example (2) and 20 g of the organic-inorganic composite particles obtained in Synthesis Example (3) are placed in a 300 ml beaker, mixed with a spatula, and 50 g of water is added thereto. The core fine particles were dispersed by applying ultrasonic waves (dispersion C2).

  Dispersion C2 was placed in a 300 ml flat bottom separable flask equipped with a stirrer, 6 g of the solution of compound (a) was added with stirring (rotation speed 200 rpm), and the temperature was raised to 40 ° C. After maintaining at the same temperature for 3 hours, 150 ml of water was added and cooled to room temperature to obtain coated fine particles D3. Further, Ni plating was applied to the coated fine particles D3 by the same method as in Production Example 1 above. Table 2 shows the characteristics of the obtained melamine-coated particles D3.

Production Example 4
Dispersion C1 was placed in a 300 ml flat bottom separable flask equipped with a stirrer, 6 g of the solution of compound (a) was added with stirring (rotation speed 200 rpm), and the temperature was raised to 50 ° C. After maintaining at the same temperature for 1 hour, 150 ml of water was added and cooled to room temperature to obtain coated fine particles D4. Further, Ni plating was applied to the coated fine particles D4 in the same manner as in Production Example 1 above. Table 2 shows the characteristics of the obtained coated fine particles D4.

Production Example 5
10 g of the solution of the compound (b) obtained in Synthesis Example (2) and 20 g of the polystyrene particles obtained in Synthesis Example (4) are placed in a 300 ml beaker, mixed with a spatula, and 50 g of water is added thereto. The core fine particles were dispersed by applying ultrasonic waves (dispersion C3).

  Dispersion C3 was placed in a 300 ml flat bottom separable flask equipped with a stirrer, and 6 g of the solution of compound (a) was added with stirring (rotation speed: 200 rpm), and the temperature was raised to 50 ° C. After maintaining at the same temperature for 1 hour, 150 ml of water was added and cooled to room temperature to obtain coated fine particles D5. Further, Ni plating was applied to the coated fine particles D5 by the same method as in Production Example 1 above. Table 2 shows the properties of the obtained coated fine particles D5.

Production Example 6 Formation of Conductive Layer Electroless nickel plating was performed on the coated fine particles D3 obtained in Production Example 3 without performing etching, and a nickel-gold plating layer was formed by a gold substitution reaction to obtain conductive fine particles.

  The gold plating layer was formed as follows. Electroless plating solution with a temperature of 60 ° C. under stirring (composition of ethylenediaminetetraacetic acid-4Na 10 g / l, citric acid-2Na 10 g / l, potassium cyanide 3.0 g / l, and Au 2.1 g / l) And an aqueous solution prepared to have a pH of 6 with an aqueous sodium hydroxide solution), and nickel-plated fine particles were added thereto, followed by Au plating treatment. After the treatment, the fine particles plated with Au were filtered and washed, and dried with a vacuum dryer (100 ° C.) to obtain conductive fine particles coated with Au on the Ni coating.

  When the plating properties of the obtained conductive fine particles were observed with an SEM (scanning electron microscope) and XMA (X-ray microanalyzer), the surface of the coated fine particles was covered with Ni, and a gold plating layer was formed thereon. It was confirmed that

Production Example 7
10 g of the solution of the compound (b) obtained in Synthesis Example (2) and 20 g of the organic-inorganic composite particles obtained in Synthesis Example (3) are placed in a 300 ml beaker and mixed with a spatula. 20 g of methanol was added, and ultrasonic waves were applied to disperse the organic-inorganic composite particles (dispersion C4).

  Dispersion C4 was placed in a 300 ml flat bottom separable flask equipped with a stirrer, heated to 70 ° C. with stirring (rotation speed 200 rpm), and then glycerol polyglycidyl ether (manufactured by Nagase Chemitex Co., Ltd., Denacol EX-145). 3 g was added. After maintaining at the same temperature for 1 hour, 150 ml of water was added and cooled to room temperature to obtain epoxy-coated particles. The obtained particles were washed, classified, and dried to obtain epoxy-coated fine particles D6. Further, Ni plating was applied to the coated fine particles D6 by the same method as in Production Example 1. Table 2 shows the properties of the obtained coated fine particles D6.

Production Example 8
Using the core fine particles (organic-inorganic composite particles) obtained in Synthesis Example (3), electroless Ni plating and gold substitution reaction were performed in the same manner as in Production Example 6 above, and the nickel-gold plating layer was formed. Fine particles were obtained. Table 2 shows the evaluation results of the plating properties of the obtained conductive fine particles.

Production Example 9
Using the polystyrene particles obtained in Synthesis Example (4), electroless Ni plating and gold substitution reaction were performed in the same manner as in Production Example 6 to obtain conductive fine particles on which a nickel-gold plating layer was formed. Table 2 shows the evaluation results of the plating properties of the obtained conductive fine particles.

Production Example 10
In a 300 ml beaker containing 50 g of water, 20 g of the core fine particles obtained in Synthesis Example (3) were put, and ultrasonic waves were applied thereto to disperse the core fine particles (dispersion C5).

  The dispersion C5 was placed in a 300 ml flat bottom separable flask equipped with a stirrer, 6 g of the compound (a) solution was added with stirring (rotation speed 200 rpm), and the temperature was raised to 40 ° C. Aggregates and precipitates formed when minutes passed. When the precipitate was observed with an optical microscope, it was confirmed that the core fine particles were aggregated together with a large number of scale-like precipitates. In addition, since single particle | grains were not able to be taken out from a deposit, plating property evaluation was not performed.

Production Example 11
20 g of the core fine particles (organic-inorganic composite particles) obtained in Synthesis Example (3) and 0.5 g of sodium dodecylbenzenesulfonate are placed in a 300 ml beaker, mixed with a spatula, 30 g of water is added thereto, and ultrasonic waves are added. Was applied to disperse the core fine particles (dispersion C6).

  Dispersion C6 was placed in a 300 ml flat bottom separable flask equipped with a stirrer, heated to 90 ° C. with stirring (200 rpm), and then 6 g of the compound (a) obtained in Synthesis Example (1). And 5 g of a 10 mass% dodecylbenzenesulfonic acid aqueous solution was added. After holding at the same temperature for 8 hours, 150 ml of water was added and cooled to room temperature to obtain melamine-coated particles. Since the obtained particles were agglomerated, they were washed, dried, pulverized, classified and purified, and polymer-coated particles D7 were obtained.

  The coated fine particles D7 were plated with Ni by the same method as in Production Example 1. The characteristics of the obtained coated fine particles D7 are shown in Table 2.

  From Table 2, it can be seen that the coated fine particles having the polymer coating layer according to the present invention exhibit good plating properties. On the other hand, Production Examples 8 and 9 having no polymer coating layer were inferior in plating properties.

It is a cross-sectional schematic diagram of the coated fine particles of the present invention. It is a cross-sectional schematic diagram of the electroconductive fine particles of this invention. It is an electron microscope (SEM) photograph which shows the core microparticles | fine-particles before polymer coating layer formation (synthesis example (3)). It is an electron microscope (SEM) photograph which shows the core microparticles | fine-particles after polymer coating layer formation (manufacture example 1).

Explanation of symbols

1 Core fine particle 2 Polymer coating layer 3 Conductor layer

Claims (7)

  A coated fine particle comprising a polymer coating layer formed by ring-opening and / or polycondensation reaction on the surface of a core fine particle composed of an organic material or an organic-inorganic composite material.   The coated fine particles according to claim 1, wherein the average particle diameter is 1.0 to 100 µm, and the coefficient of variation (Cv value) of the particle diameter is 10% or less.   The polymer coating layer includes a polymer having at least one selected from the group consisting of an amino group, an imino group, a carboxyl group, a hydroxyl group, an epoxy group, a sulfonic acid group, an aldehyde group, and a phosphoric acid group. Item 3. The coated fine particles according to Item 1 or 2. A method for producing coated fine particles having a polymer coating layer on the surface of core fine particles made of an organic material or an organic-inorganic composite material,
A method for producing coated fine particles, wherein the polymer coating layer is formed by ring-opening and / or polycondensation reaction in an aqueous medium in which the core particles are dispersed in the presence of a surfactant. The method for producing coated fine particles according to claim 4, wherein a compound having a structure represented by the following general formula is used as the surfactant.
R ^1- (CH ₂ -CH ₂ -O-) _n -X _m -R ²
(Wherein, R ¹ is an aliphatic or aromatic hydrophobic group having 5 to 25 carbon atoms, and R ² is a polymer chain having a polyamine structure or polycarboxylic acid structure having a weight average molecular weight of 300 to 10,000. , N represents an integer of 3 to 85, and X is derived from a group capable of reacting with at least one group selected from the group consisting of an amino group, an imino group and a carboxyl group, and is formed after the above reaction. And m represents 1 or 0.)   The polymer coating layer has a structure obtained by a polycondensation reaction between formaldehyde and at least one selected from the group consisting of urea, thiourea, melamine, benzoguanamine, acetoguanamine, and cyclohexylguanamine. 6. A method for producing coated fine particles according to 4 or 5.   Conductive fine particles, wherein a conductor layer is formed on the surface of the coated fine particles according to any one of claims 1 to 3.